Chair frame



FIG. 1 is a front perspective view of a chair frame comprising the new design;

FIG. 2 is a rear perspective view thereof;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a right side elevational view thereof, where the left side elevational view is a mirror image thereof; and,

FIG. 6 is a top plan view thereof.

The broken lines shown are for illustrative purposes only and form no part of the claimed design. 

The ornamental design for the chair frame, as shown and described. 